Air driven on-line separation and preconcentration on a C-18 column coupled with thermospray flame furnace AAS for the determination of cadmium and lead at mu g l(-1) levels

A simple and sensitive method for the determination of cadmium and lead at mug l(-1) and sub-mug l(-1) levels by on- line separation and preconcentration coupled with thermospray flame furnace AAS ( TS- FF- AAS) was developed. Compressed air was used to drive the sample through the 3 cm HPLC C-18 RP column and the 500 mul eluate to the TS- FF- AAS. The chelating reagent ammonium pyrrolidinedithiocarbamate was immobilized onto the column as a solution in the eluent ( 60% v/ v methanol) simultaneously with the elution of the previous preconcentrated sample. Loading of sample volumes up to 20 ml was possible. The detection limits for cadmium and lead using 20 ml sample volume were 0.007 and 0.17 mug l(-1), respectively. RSD values were typically about 4%. The combined effect of preconcentration and TS- FF- AAS yielded enhancement factors towards conventional flame AAS of 1960 and 610 for cadmium and lead, respectively.